I've got the indicators working, well sort of. Two local radio stations that I tried showed the TP and TA indicators exactly as they should ......

......but, the two largest national stations (radio 1 and 2) have the TA indicator on permanently and the TP indicator never (TP is possibly correct for these stations). This I know to be wrong from having these stations tuned into a HU.

Obviously all of this results in the tuner not switching to a station when the TA comes on.

Well that explains it then. It should switch to a station when a TA flag comes on. That's the whole point in TA.
So what is/does the event ONTASTART do?

ONTASTART will do whatever you define in Exectbl.ini for it to do.. thing is, I was under the impression that with only ONE tuner, you can only know if the CURRENTLY TUNED STATION's TA/TP status (and there's no way to know if any other station's TA/TP status).